In Deut 6:4-5, we are given the Shema Israel, which was recited morning and evening as the prayer of Israel and considered to contain all the principles of the Decalogue. Since the Decalogue is the summary of God's Laws, then the Shema Israel could be considered the summary of the summary of God's Laws .Jesus cited this as the "first and greatest commandment" in Matt 22:37
"Hear, O Israel, the Lord our God is one Lord. And thou shalt Love the Lord they God with all thine heart, and with all thy soul, and with all thy might." Deut. 6:4-5
When we have only one God and worship only one God, then we begin to see that there is unity and purpose and providence in everything created and happening. We get a little glimpse of thinking God's thoughts after him. Therefore, for the Biblical thinking Christian there is a uni-verse, a unifying thread connecting every subject and detail, it is God's design and purpose which can often be, at least partially, discovered and result in bringing Him Glory. The alternative to a universe is a multiverse with no unifying truth, just randomness, purposeless, matter and actions.
Praise God for His unified universe! These are some of the thoughts that give rise to connecting discussions in mathematics and science with sociology, economics, psychology, evangelism and everything else. Because they really are related in real life through God's purposes. A secular viewpoint keep the subjects disconnected from each other, real life, practical applications, history, and the news. Do you see how that could take the joy and blessing out of learning!